High-Precision Forged Pinion Shaft for Industrial Gearboxes

The pinion shaft is the integrated shaft-and-pinion component that transmits torque from the gearbox or motor directly into the girth gear mesh. It serves double duty: the shaft section must maintain precise alignment under bending and torsional loads, while the pinion teeth must deliver accurate mesh geometry at the same time. Any runout in the shaft translates directly into mesh error at the tooth contact, accelerating wear on both the pinion and the mating girth gear.

Hanwei manufactures pinion shafts as single-piece forgings, ensuring uninterrupted grain flow from the shaft body through the pinion tooth roots. This forging continuity delivers significantly better fatigue resistance compared to shrink-fitted or bolted pinion-shaft assemblies, particularly at the critical transition zone where shaft meets pinion.

Our process begins with alloy steel forgings, normalized and tempered to the specified core hardness. After CNC turning and gear hobbing, the pinion teeth are finish-ground to DIN Grade 6 on our precision grinding machines. Shaft journals are ground to IT5 tolerance or better, with surface roughness Ra ≤ 0.8 μm, ensuring smooth bearing operation and minimal vibration.

Coaxiality between the shaft journals and the pinion pitch cylinder is controlled to within 0.02 mm—a specification that directly determines the mesh quality of the pinion-girth gear pair. We verify this with on-machine measurement after every grinding pass.

For replacement orders, we match the existing shaft's coupling dimensions, bearing seat geometry, and pinion tooth data. When original drawings are unavailable, our reverse-engineering service captures all parameters from the installed component. Warranty: 1 year standard, 3 years for special designs. Send your pinion shaft specifications or request our field measurement service.